The present invention relates generally to multiple piece fastener head cover assemblies. More particularly, the present invention relates to a two-piece decorative assembly having an anchor base member adapted to be secured by a fastener such as a screw or the like, and a cooperating upper cap which snap-fits to the anchor and is releasably, semi-permanently secured thereto.
In the prior art a variety of both plastic and metallic devices are known. In most applications where a fastener such as a screw, bolt or the like is inserted upon a workpiece, the external head of the fastener or screw is left visually apparent to the consumer of the workpiece. Obviously this may present deleterious aesthetic objections. Accordingly, a number of prior art inventions have been proposed wherein multiple piece items are employed in conjunction with the fastener to cover the head thereof once the apparatus is installed.
U.S. Pat. No. 4,129,060 discloses a self closing cover which "shuts" when the fastener is installed. Related art is also seen in U.S. Pats. Nos. 2,548,004; 1,936,624; 3,979,803; 1,805,937; 4,136,598; 4,316,690; 2,513,182; 2,931,005; 465,289; 1,644,475; 2,654,927; 3,979,802 and 3,881,391. A related two piece assembly of extremely complex and limited geometry is shown in U.S. Pat. No. 3,930,432. It is believed that the latter reference is the most relevant American patent known to me. The fastener device of U.S. Pat. No. 3,618,444 covers the head of the fastener, while also sealing the surface of the member into which the fastener is installed. U.S. Pat. No. 4,154,138 discloses a complex screw assembly equipped with a plastic head covering.
A variety of foreign patents are known which relate to the present concept. United Kingdom patent No. 345,745 is believed to be the most relevant of the foreign patents known to me. Other relevant U.K. patents include numbers 870,160; 916,161; 916,162; and, 890,049. Other relevant foreign prior art patents include French patents Nos. 1,175,054 and 1,397,500; Canadian patent no. 784,462, and Russian patent No. 483,543.
However, to be reasonably practical, the fastener covering assembly must install quickly and easily upon a workpiece without breaking. Similarly, the fastener must be capable of being removed where necessary to permit subsequent maintenance upon the object or workpiece to which the covered fastener is assembled. Accordingly the cover assembly must be capable of rapid manual assembly, but the "snap-fit" structure must not crack in response to pressure or unnecessarily deform in response to time. It is also advantageous to provide such a structure with inherent mechanical resistance to temperature variations.